There is a classic story of the Bedouin Arab, his camel and his tent. the shivering camel begs his master to allow him to put his nose in the warm tent, then asks to do the same with his front legs, then for his hump to enter the tiny tent, and finally, with complete disregard for his masterâ€™s kindness, the beast kicks the man out from the tent altogether!

The advocates for DDT are akin to the camel in the story. They have just won a hard lobby to get the government of Uganda to initiate indoor spraying of the pesticide in the fight to eradicate malaria-carrying mosquitoes.

On Friday, health minister Dr. Stephen Malinga launched the Indoor Residual Spraying (IRS) at Maziba Primary School playground in Ndorwa East, Kabale district. Now, you would think that the advocates of DDT would be content, but you would be dead wrong. Their next big push is to get the government to agree to largescale outdoor spraying of DDT.

For example, last week in this paper, Professor Donald Roberts correctly pointed out that there are currently no known harm in using DDT within the confines of building to eradicate the deadly mosquitoes. Yet, the world respected scientist of tropical public health, also went on to say, â€œAdditionally, environmental exposure to DDT does not cause birds to lay eggs with transparent membranes instead of hard shells.â€ Here, Dr. Roberts is just flat out wrong.

Although the laying of shell-less eggs is rare (it was observed in Brown Pelicans nesting off the coast of California), the laying of thin- shelled eggs owing to the biochemical effects of DDE on the process of shell formation was widespread among many species of birds in North America and Europe during the peak period of DDT use in the 1950s to early 1970s.

The species most severely affected were raptors such as Peregrine Falcon, Bald Eagle, Osprey, and fish-eaters such as the pelican and some herons that underwent simultaneous population declines in the period when eggshells were abnormally thin and were either broken in incubation or failed to hatch.

Furthermore, in his book titled Population Limitations in Birds (Academic Press, 1998), Dr. Ian Newton demonstrates the clear link between pesticides and pollutants and their impact on bird population.

In the book, he brings together 16 studies that demonstrated the demise of birds over large geographical areas as a result of pesticide use, and nine other studies showing the immediate effects of pesticides on bird numbers.

In addition, there are literally hundreds of other studies on the subject out there. Why, one asks, with so much research information available on the impact of DDT on some species of North American birds, would the good professor say something that he knows is patently untrue? The reason, as previously noted in this column, is that DDT is probably the most effective known pesticide against insects including malaria-causing mosquitoes.

Easy to manufacture, cheap and effective against most insects including the anopheles mosquitoes, which carry the deadly malarial parasites that kill millions every year, its widespread use in North America in the 1950s and 1960s is credited with eradicating malaria-carrying mosquitoes altogether. As well, research show that wherever it is used, there is a tangible decline in malaria-related deaths.

The problem is that the dramatic effectiveness of DDT in North America came about precisely because of its large scale use, including aerial spraying over the environment in order to eliminate certain insects including the mosquitoes in their own breeding grounds in the swamps and stagnant waters. For example, in order to get rid of the gypsy moth, the US Department of Agriculture carried out aerial spraying of millions of acres in New York State in 1950s, including Long Island.

Whatâ€™s more, DDT was mixed with oil to make it stick to the trees. And, as noted above, there was a real environmental cost attached to the indiscriminate use of the pesticide.

American biologist Rachel Carson in her highly influential book Silent Spring, published in 1962, explains that many species of peregrine falcons, eagles, songbirds, brown pelicans, California sea lions and many fishes had dwindled to dangerously low numbers because of DDT poisoning.

Consequently, Canada banned DDT use in 1969. Meanwhile, on June 30, 1972, the US Environmental Protection Agency banned the insecticide altogether.

Scientists in Canada and United States who painstakingly nursed the species back from the brink of extinction have since upgraded the peregrine falcon from endangered list after three decades of heroic effort.

Now, like the wily camel in the above story, the advocates of DDT know that so long as the pesticide is limited only inside homes and buildings, the bulk of mosquitoes will continue to breed out there.

They also know that DDT is the most cost-effective approach to eliminate mosquitoes in swamps and stagnant waters. Yet, they are also keenly aware that there will be fierce opposition worldwide to widespread environmental spraying of DDT.

Uganda, after all, according to Birdlife International, has one of the richest variety of birds in the world with 1062 species, including as many as 70 in the falcon family alone.

Naturally, by arguing that DDT has no demonstrated impact on birds, advocates like Professor Roberts can later argue for the large scale spraying of DDT. Thatâ€™s what was argued in the 1950s in North America with the catastrophic result still being felt today. Never again.

Uganda must continue to look for alternatives to eradicating mosquitoes without harming the environment. At the same time it must strengthen laws on outdoor spraying of DDT with hefty fines, and possible jail term for repeat violators.

Opiyo.oloya@sympatico.ca

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